1. Field of the Invention
The present invention relates to a gasket used in the automobile and so on, especially in the automotive engine and, more particularly, to a gasket adapted for the use in concurrent sealing of three set of mating surfaces at an area, called tri-face area herein, where three engine components, for example cylinder block, cylinder head and chain block, or cylinder block, oil pan and front cover meet together and come into abutment against one another when assembled to complete the automotive engine.
2. Description of the Prior Art
With the automotive engine of the type in which a timing-chain housing is attached to the combined cylinder block and cylinder head, a tri-face area is commonly found where the cylinder block, cylinder head and timing-chain housing meet together and come into abutment against one another. In engine construction in which an oil pan is installed on the bottom of the cylinder block, moreover, the tri-face area is formed where all the oil pan, cylinder block and a front cover or flywheel housing are brought into abutment one another. Conventionally any gasket of peculiar construction has been developed to seal concurrently joints between any mating surfaces in the tri-face area. For example, a gasket making sure of secure sealing at the tri-face area has been well known in which a fluid gasket so called FIPG: Fluid In Place Gasket is employed along with a solid gasket made in some form conforming to the tri-face area.
Disclosed in Japanese Utility Model laid-Open No. 61561/1985 is an example of the prior sealing means, in which a plate-like gasket is placed and squeezed between first and second components, while a fluid gasket is arranged between the mating surfaces at a tri-face area where a third component comes into abutment against both the first and second components stated earlier. The plate-like gasket is made in any one of stepped, inclined and undulated contours along an edge thereof facing the fluid gasket, thus partially biting into the fluid gasket at peaks extending towards the third component in the direction across the thickness of the fluid gasket, while not reaching the fluid gasket at recessions retreating away from the third component.
Japanese Utility Model Laid-Open No. 148962/1986 discloses a gasket for a tri-face area, in which a gasket plate with corrugated bead is clamped between the first and second components while a fluid gasket material is placed between the mating surfaces at a tri-face area where a third component comes into abutment against both the first and second components, and a gasket material apart from the fluid gasket material is charged nearby a bead end at a gasket edge in the tri-face area.
Japanese Patent Laid-Open No. 73859/2000 discloses a sealing means for an engine in which a timing-chain housing is joined with tightening bolts onto the sides of a cylinder block and a cylinder head that are tightened together through a head gasket. With the prior sealing means stated just above, both the cylinder head and the cylinder block are partially recessed on the sides thereof, while the gasket prior to placing it between the mating surfaces of the cylinder head and the cylinder block is applied with a deposit of fluid gasket material in such a way that the fluid gasket material fills the recesses when the cylinder head and the cylinder block are joined together, thus making sure of reliable sealing at the tri-face area.
Another prior sealing means to join a timing-chain housing over both the sides of the cylinder head and the cylinder block is disclosed in Japanese Patent Laid-Open No. 73860/2000, in which a soft sealant such as fluid gasket, and so on is placed in bounds where all the cylinder head, cylinder block and the side wall of the timing-chain housing meet together and come into abutment against one another.
A series of silicon compounds has been predominantly used for the prior fluid gasket applied at the tri-face area as recited earlier. Nevertheless, this type of fluid gasket by nature has no adhesive property and, even with any adhesive property, would be too sparse in adhesive property or bonding ability to make sure of safe sealing performance. With the prior gaskets of the type stated earlier, accordingly, the conventional fluid gasket is commonly poor in adhesive property or bonding characteristic with the solid gasket and tends to easily come off the solid gasket owing to any vibration or any thermal load that might raise the repeated thermal expansion/shrinkage. This causes oil leakage at the tri-face area in the engine construction, raising a major problem of spoiling reliability in the aspect of the sealing performance at the tri-face area. This major problem remaining unsolved in the prior gaskets teaches that the only sealing means in which the fluid gasket is simply combined with the solid gasket, even though refined by adding any somewhat sophisticated process of charging or applying a deposit of fluid gasket material to the tri-face area at the time of assembling, is quite tough to make sure of the sealing performance or reliability enough to justify any increase in production steps and/or costs.
It is the primary object of the present invention to provide a gasket in which a fluid gasket material is used along with a solid gasket material to seal a tri-face area where three engine components meet together and come into abutment against one another, and more particular to provide the improvement in the gasket of the type recited earlier, in which adhesive property or bonding ability between the fluid and solid gasket materials is made better to get the sealing performance up to more reliability.
The present invention is concerned with a gasket adapted to be disposed in a construction that is comprised of a first component, a second component confronting the first component through a solid gasket material interposed between the first and second components, and a third component arranged in opposition to flush sides of the first and second components, all the first, second and third components meeting together and coming into abutment against one another to form a tri-face area; the improvement characterized in that a fluid gasket material is filled in the tri-face area while a deposit of bonding agent is applied on an end of the solid gasket material, which is placed in the tri-face area, and the fluid gasket material is joined to the solid gasket material with the bonding agent.
According to one aspect of the present invention, a gasket is disclosed in which the end of the solid gasket material on which the bonding agent is applied is exposed out of mating surfaces of the first and second components into the tri-face area.
According to another aspect of the present invention, a gasket is disclosed in which the bonding agent is applied on either a tip face or at least one side on the end of the solid gasket material.
According to another aspect of the present invention, a gasket is disclosed in which the end of the solid gasket material exposed out of the mating surfaces of the first and second components is placed in an area where both the first and second components are cut at their confronting edges to form bevels opposite to one another.
According to another aspect of the present invention, a gasket is disclosed in which the bonding agent is applied previously to the end of the solid gasket material, preparatory to installation of the solid gasket material into the construction.
According to another aspect of the present invention, a gasket is disclosed in which the bonding agent and/or a primer to be applied on the solid gasket material are applied with either dipping or printing process.
According to a further another aspect of the present invention, a gasket is disclosed in which the first component is a cylinder block, the second component is a cylinder head to be joined to the cylinder block and the third component is a timing-chain housing to be fastened to both the cylinder block and the cylinder head. As an alternative, a gasket is provided in which the first component is a cylinder block, a second component is a front cover fastened to the cylinder block, and the third component is an oil pan to be joined together to the cylinder block.
The gasket constructed as stated earlier may be kept safely against any cracking that might otherwise occur between the solid gasket material and the fluid gasket material at the tri-face area where the three components meet together and come into abutment against one another. Thus, the present invention makes sure of improvement in adhesive property and close adherence of the solid gasket material with the fluid gasket material, making better the sealing performance at the tri-face area in the construction. The bonding agent is applied on the exposed end of solid gasket material, whether partially or throughout of the exposed end. As an alternative, any primer for surface pretreatment may be applied preparatory to the application of the bonding agent to the solid gasket material. The primer having any adhesive property may be used as the bonding agent alternatives in return for the bonding agent.
With the tri-face gasket constructed as stated earlier, the bonding agent deposited on the solid gasket material helps make sure of joining securely the solid gasket material to the fluid gasket material filled in the tri-face area, thus improving distinctly the adhesive property and close adherence of the fluid gasket material with the solid gasket material, compared with the prior tri-face gasket in which the fluid gasket material comes into engagement with the solid gasket material with no bonding agent applied on the solid gasket material. The tri-face gasket of the present invention realizes the perfect sealing at the tri-face area, preventing any oil leakage at the tri-face area. Thus, the present invention provides the tri-face gasket high in reliability of sealing performance compared with the prior gasket with no bonding agent, thus expected to find increased application in various kinds of sealing construction.
Other aspects and features of the present invention will be more apparent to those skilled in the art on consideration of the accompanying drawings and following specification wherein are disclosed preferred embodiments of the invention with the understanding that such variations, modifications and elimination of parts may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.